Calculate the speed to which a stationary H atom would be accelerated if it absorbed a photon of wavelength 400 nm.4

v=9.98*10⁻⁴m/s

Explanation:

From De Broglie's wavelength equation which is expressed as

λ=h/p

where h=planks constant, with value 6.626*10⁻³⁴J

p is the momentum expressed as p=mv

where m=mass and v=velocity. Hence we can rewrite the wavelength equation as

λ=h/mv

mass of hydrogen is given as m=1.66*10⁻²⁴kg

hence if we make the speed the subject of formula we have

V=h/mλ

V=(6.626*10⁻³⁴J)/(1.66*10⁻²⁴kg*400*10⁻⁹)

v=9.98(10⁻³⁻³⁴⁺²⁴⁺⁹)

v=9.98*10⁻⁴m/s